(1) Field of the Invention
The present invention relates to substrate cleaning apparatus and methods for supplying a cleaning solution from a nozzle to and cleaning substrates such as semiconductor wafers, glass substrates for liquid crystal displays, glass substrates for photomasks, substrates for optical disks and the like. More particularly, the invention relates to a technique of performing a cleaning process by using a two-fluid nozzle for forming mist by mixing a cleaning solution and a pressurized gas.
(2) Description of the Related Art
In a conventional substrate cleaning apparatus for cleaning substrates, the substrates are supported by a chuck type device that supports each substrate at edges thereof, for example.
However, in the substrate cleaning apparatus with the chuck type device for supporting a substrate at edges thereof, support pins that support the edges of the substrate are obstructive to a cleaning operation. Consequently, the edges of the substrate cannot be cleaned.
When removing minute particles, a physical cleaning is used. For example, a scrub cleaning is carried out in which a brush or sponge is placed in direct contact with the substrate spinning at high speed. However, such a physical cleaning cannot clean the edges of the substrate since the brush or sponge contacts the support pins.
To solve this problem, the conventional apparatus requires a mechanism for retracting the support pins to realize an unhindered cleaning operation. Alternatively, a separate, dedicated edge cleaning unit must be installed.
In such a case, however, the apparatus has a complicated construction, and the processing time is extended.